Sound collecting device and sound collecting method

ABSTRACT

A sound collecting device includes a sound source position input interface that receives input of sound source position information indicating a sound source position, an audio interface that receives input of sound signals collected by two or more sound collecting units placed at predetermined positions in advance, a recording medium in which sound collecting unit placement information indicating placement information of the sound collecting units is stored, and a controller that selects one of the sound signals output from the sound collecting units, based on the sound source position information and the sound collecting unit placement information.

BACKGROUND

1. Technical Field

The present disclosure relates to a sound collecting device and a soundcollecting method for collecting a sound.

2. Description of the Related Art

Unexamined Japanese Patent Publication No. 2008-193196 discloses aconfiguration for generating, when a specific object is designated for acaptured image, a synthesized sound signal corresponding to the object,from a plurality of sound signals. With this configuration, only a soundemitted from the designated object can be emphasized and reproduced.

SUMMARY

The present disclosure provides a sound collecting device and a soundcollecting method that are effective for sound collection at adesignated position.

A sound collecting device according to an exemplary embodiment of thepresent disclosure includes a sound source position input interface thatreceives input of sound source position information indicating a soundsource position, an audio interface that receives input of sound signalscollected by two or more sound collecting units placed at predeterminedpositions in advance, a recording medium that stores sound collectingunit placement information indicating placement information of the soundcollecting units, and a controller that selects one of the sound signalsoutput from the sound collecting units, based on the sound sourceposition information and the sound collecting unit placementinformation.

A sound collecting method according to an exemplary embodiment of thepresent disclosure includes a first step of receiving input of soundsource position information indicating a sound source position, a secondstep of receiving input of two or more sound signals collected by soundcollecting units placed at predetermined positions in advance, and athird step of selecting one of the sound signals output from the soundcollecting units, based on the sound source position information andsound collecting unit placement information indicating placementinformation of the sound collecting units.

The sound collecting device and the sound collecting method according tothe present disclosure are effective for sound collection at adesignated position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a configuration of a soundcollecting system including a sound collecting device according to afirst exemplary embodiment;

FIG. 2 is an overhead view illustrating an example of a relationshipamong a sound source position, positions of microphones, and an imagingrange of a camera, in the first exemplary embodiment;

FIG. 3 is a flowchart illustrating processing of the sound collectingdevice according to the first exemplary embodiment;

FIG. 4 is an overhead view illustrating an example of a relationshipbetween positions of seats and those of microphones, in a secondexemplary embodiment;

FIG. 5 is an overhead view illustrating an example of a relationshipamong a sound source position, positions of microphones, and placementof an obstacle, in a third exemplary embodiment; and

FIG. 6 is a flowchart illustrating processing of a sound collectingdevice according to the third exemplary embodiment.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described in detail, withreference to the drawings as appropriate. However, a detaileddescription more than necessary may be omitted, such as a description ofa well-known item and a duplicate description for a substantiallyidentical component, to avoid an unnecessarily redundant description andto allow those skilled in the art to easily understand the followingdescription.

Note that the accompanying drawings and the following description areprovided for those skilled in the art to well understand the presentdisclosure and are not intended to limit the subjects described in theclaims.

First Exemplary Embodiment 1. Configurations of Sound Collecting Systemand Sound Collecting Device

FIG. 1 is a block diagram illustrating a configuration of a soundcollecting system including a sound collecting device according to afirst exemplary embodiment. In FIG. 1, the sound collecting systemincludes sound collecting device 100, client 200, camera 301 a, camera301 b, microphone 302 a, and microphone 302 b. Camera 301 a and camera301 b are collectively referred to as cameras (imaging units) 301. Inthe present exemplary embodiment, a configuration including two cameras301 will be described; however, the number of cameras 301 may be atleast one. Microphone 302 a and microphone 302 b are collectivelyreferred to as microphones (sound collecting units) 302. In the presentexemplary embodiment, a configuration including two microphones 302 willbe described; however, the number of microphones 302 may be at leasttwo.

Sound collecting device 100 includes CPU (controller) 101, memory(recording medium) 102, network interface (sound source position inputinterface) 103, video interface 104, and audio interface 105.

CPU 101 executes a computer program stored in memory 102, and selects anoptimal microphone among microphones 302 used for sound collection. Withthis selection, a piece of sound data output from microphones 302 isselected. A method for selecting the optimal microphone will bedescribed later.

Memory (recording medium) 102 stores positional coordinates at whichcameras 301 and microphones 302 are placed, in a coordinate system thatis arbitrarily defined in a space where the sound collecting system isinstalled. The positional coordinates of microphones 302 are examples ofsound collecting unit placement information indicating placementinformation of microphones 302. The positional coordinates of cameras301 are examples of imaging unit placement information indicatingplacement of cameras 301.

In addition, memory 102 stores specific position information indicatingone or more specific positions in a predetermined space. Example of thespecific position information is a sound source position, positions ofseats placed or so on in the predetermined space (the details thereofwill be described later.)

Network interface (sound source position input interface) 103 isconfigured to establish communications of sound collecting device 100with client 200. Network interface 103 receives sound source positioninformation indicating a sound source position. More specifically,network interface 103 receives a pixel position in image data, whichindicates the sound source position of the sound (an example of soundsource position information) from client 200, and transmits the pixelposition to CPU 101. Further, network interface 103 transmits to client200 image data and sound data sent from CPU 101.

Video interface 104 is configured to connect cameras 301 to CPU 101.More specifically, image interface 104 is connected to one or morecameras (imaging units) 301 placed in advance at a predeterminedposition to capture images of a predetermined range.

Audio interface 105 is configured to connect microphones 302 to CPU 101.Audio interface 105 receives two sound signals that are collected bymicrophones (sound collecting units) 302 placed in advance atpredetermined positions.

Client 200 includes CPU 201, memory 202, network interface 203, andinput and output interface 206. Client 200 is connected to soundcollecting device 100 via network interface 203.

Input and output interface 206 includes, for example, display 206 a,touch panel 206 b, and speaker 206 c. Display 206 a receives image datacaptured by cameras 301 through sound collecting device 100 to displaythe received image data. A user designates a specific position in animage, using touch panel 206 b on display 206 a. Speaker 206 c receivessound data collected by microphones 302 through sound collecting device100 to reproduce the received sound data.

Cameras 301 are installed, for example, at a ceiling part in a cabin ofan aircraft. Cameras 301 send the captured image data to soundcollecting device 100.

Microphones 302 are installed, for example, at the ceiling part in thecabin of the aircraft. Microphones 302 send the collected sound data tosound collecting device 100.

CPU 101 is an example of a controller. Memory 102 is an example of arecording medium. Network interface 103 is an example of a sound sourceposition input interface for receiving the sound source positioninformation indicating the sound source position of the sound. Cameras301 are examples of imaging units. Microphones 302 are examples of soundcollecting units.

2. Operation of Sound Collecting Device

Hereafter, an operation of sound collecting device 100 configured asdescribed above will be described.

FIG. 2 is an overhead view illustrating an example of a relationshipamong the sound source position, the positions of microphones 302, andthe imaging range to be captured by cameras 301. In FIG. 2, cameras 301are installed, for example, at the ceiling part in the cabin of theaircraft. Therefore, the imaging range is set to fall within a frameillustrated in FIG. 2. The head and nose of a passenger viewed fromabove appear near a center of the imaging range in FIG. 2. Positions ofthe imaged head and nose indicate that the passenger is directed to theleft direction in FIG. 2. More specifically, it is considered that thepassenger stands (or sits) with microphone 302 a located ahead of thepassenger and microphone 302 b located behind the passenger. Here, soundsource position P is designated as an arbitrary position in the imagingrange. In FIG. 2, sound source position P indicates a position at whichthe passenger is present.

Microphone 302 a is placed at the position in FIG. 2, which is spacedapart from sound source position P (the position at which the passengeris present) by distance Da, and its positional coordinate is expressedas microphone position Pa. In other words, microphone 302 a is locatedat place Pa ahead of the passenger, which is spaced apart from thepassenger by distance Da.

Microphone 302 b is placed at the position in FIG. 2, which is spacedapart from sound source position P by distance Db, and its positionalcoordinate is expressed as microphone position Pb. In other words,microphone 302 b is located at place Pb behind the passenger, which isspaced apart from the passenger by distance Db. Microphones 302 may beplaced outside the imaging range of cameras 301.

Hereafter, the operation of the sound collecting device according to thepresent exemplary embodiment will be described, using a case with theabove placement relationship as an example.

FIG. 3 is a flowchart illustrating processing of sound collecting device100 according to the present exemplary embodiment.

In FIG. 3, when receiving designation of the sound source position (theposition at which a certain passenger is present in the aircraft) fromclient 200, sound collecting device 100 first calculates sound sourceposition P (S101).

Sound source position P is designated as described below, for example.Input and output interface 206 in client 200 includes display 206 a andtouch panel 206 b (see FIG. 1). Display 206 a receives the image datacaptured by cameras 301 via sound collecting device 100 to display thereceived image data. The user then designates the arbitrary position inthe image displayed on display 206 a, using touch panel 206 b. CPU 201in client 200 calculates a pixel position corresponding to thedesignated position (an example of sound source position information) inthe image. Further, CPU 201 sends the calculated pixel position to soundcollecting device 100 via network interface 203. Thus, CPU 101 in soundcollecting device 100 calculates sound source position P from the pixelposition in the image, as a coordinate in the coordinate system that isarbitrarily defined in the space where the sound collecting system isinstalled, based on the image data captured by cameras 301 and thepositions of the cameras 301.

Subsequently, CPU (controller) 101 in sound collecting device 100determines whether a person (passenger) is present within a certaindistance range from the designated position in the image. The certaindistance range is typically a distance of several centimeters to severalmeters.

The determination whether the person is present is made as follows. CPU101 recognizes positions of the head and nose of the person (passenger)from the image in the imaging range. When determining that the person ispresent in the image, CPU 101 recognizes the positions of the head andnose of the person, and thus calculates face direction X indicating adirection to which the person is directed, as a direction to besound-collected (S102). The direction to be sound-collected is adirection in which an object emitting a sound to be collected emits thesound. In other words, the direction to be sound-collected is adirection in which the sound to be collected is emitted. Morespecifically, in a case of the person (passenger), since the personemits the sound in face direction X that is the direction to which theperson is directed, face direction X is specified as the direction to besound-collected.

Further, CPU 101 calculates a weighting factor for each microphone 302,based on a relative position with sound source position P and facedirection X as references (S103). Next, a method for determining theweighting factors in the present exemplary embodiment will be describedwith reference to FIG. 2.

CPU 101 gives weighting factor w1 to microphones 302 located within anangle range from −θ to +θ centering around sound source position P witha direction indicated by face direction X as a reference. CPU 101 givesweighting factor w2 that is larger than weighting factor w1, tomicrophones 302 located outside the angle range from −θ to +θ. Morespecifically, in the case of the placement relationship illustrated inFIG. 2, CPU 101 gives weighting factor w1 to microphone 302 a locatedwithin the angle range from −θ to +θ, and gives weighting factor w2 tomicrophone 302 b located outside the angle range from −θ to +θ.

Values of angle θ, weighting factor w1, and weighting factor w2 aredetermined as prior information, for example, based on knowledge aboutdependency between attenuation of a sound pressure level of a soundemitted by a person and an angle with respect to a face direction of theperson. The values of angle θ, weighting factor w1, and weighting factorw2 are stored in memory 102 in sound collecting device 100, asprocessing parameters for CPU 101.

CPU 101 then calculates linear distances Da and Db from sound sourceposition P to respective microphones 302 a and 302 b, based on thecoordinates of microphone positions Pa and Pb stored in memory(recording medium) 102 and the calculated coordinate of sound sourceposition P (S104).

Further, CPU 101 calculates weighted distances Dwa and Dwb from soundsource position P to respective microphones 302 a and 302 b, based onweighting factors w1 and w2 determined for microphones 302 andcalculated linear distances Da and Db (S105).

Weighted distances Dwa and Dwb are calculated from, for example, thefollowing relational expressions.

Dwa=Da×w1

Dwb=Db×w2

Finally, CPU 101 selects a sound signal corresponding to microphone 302that has a minimum one of the weighted distances from sound sourceposition P to respective microphones 302 (5106). More specifically, CPU(controller) 101 selects the sound signal corresponding to the soundcollecting unit that has the minimum one of the weighted distancescalculated based on the weighting factors determined by a relativepositional relationship between the position indicated by the soundsource position information and the positions indicated by the soundcollection unit placement information, and the linear distances betweensound source position P and the respective sound collection units.

The selected sound signal is sent to, for example, client 200. Then, theuser can listen to the sound reproduced by speaker 206 c of input andoutput interface 206. Thus, the processing of sound collecting device100 is completed.

As described above, sound collecting device 100 according to the presentexemplary embodiment gives weighting factor w1 to microphones 302located within the angle range from −θ to +θ, with face direction X as areference. Further, sound collecting device 100 according to the presentexemplary embodiment gives weighting factor w2 that is larger thanweighting factor w1, to microphones 302 located outside the angle rangefrom −θ to +θ. Therefore, the weighted distances of microphones 302located within the angle range from −θ to +θ tend to have a relativelysmall value.

More specifically, CPU 101 selects the sound signal corresponding to thesound collecting unit that has the minimum one of the weighted distances(Dwa, Dwb) calculated based on the weighting factors (w1, w2) determinedby the relative positional relationship between the position indicatedby the sound source position information and the positions indicated bythe sound collection unit placement information, and the lineardistances (Da, Db) between sound source position P and respectivemicrophones (sound collection units) 302.

With the selection method described above, microphones 302 locatedwithin the angle range from −θ to +θ, that is, microphones 302 locatedin face direction X that is small in attenuation of the sound pressurelevel of the sound emitted by the person tend to be able to be selectedeasily. Accordingly, sound collecting device 100 according to thepresent exemplary embodiment can effectively collect the sound at thedesignated position.

With regard to weighting factors w1 and w2, for example, the value ofweighting factor w2 that is given to microphones 302 located outside theangle range from −θ to +θ may be set to a considerably larger value thanthat of weighting factor w1. In this case, the weighted distancescorresponding to microphones 302 located outside the angle range from −θto +θ become satisfactorily large in comparison with the weighteddistances corresponding to microphones 302 located within the anglerange from −θ to +θ. Hence, when microphone 302 that has the minimum oneof the weighted distances is selected, microphones 302 located outsidethe angle range from −θ to +θ can be set not to be selected. In otherwords, CPU 101 selects the sound signal corresponding to microphone 302that has the minimum one of the linear distances between respectivemicrophones 302 and sound source position P calculated based on thesound source position information and the sound collecting unitarrangement information, of microphones 302 located within thepredetermined angle range (−θ to +θ) centering around the direction tobe sound-collected (face direction X) with sound source position P as areference.

Without using weighting factors w 1 and w2, CPU 101 may select the soundsignal corresponding to microphone 302 that has the minimum one of thelinear distances between sound source position P and respectivemicrophones 302, of microphones 302 located within the predeterminedangle range (−θ to +θ) centering around the direction to besound-collected (face direction X) with sound source position P as areference.

By using the above described methods, the optimal microphone is selectedto effectively collect the sound at the designated position.

The coordinate system that is arbitrarily defined in the space where thesound collecting system is installed may be a two-dimensional coordinatesystem ignoring height information, or may be a three-dimensionalcoordinate system taking the height information into consideration. Inthe case of the three-dimensional coordinate system, a height of thesound source position is calculated based on image data captured by twoor more cameras 301 and the positional coordinates of cameras 301 storedin memory 102.

3. Advantageous Effects

As described above, sound collecting device 100 according to the presentexemplary embodiment includes network interface (sound source positioninput interface) 103 that receives input of the sound source positioninformation indicating the sound source position, audio interface 105that receives input of the two or more sound signals collected bymicrophones 302 placed at the predetermined positions in advance, memory(recording medium) 102 that stores the sound collecting unit placementinformation indicating the placement information of microphones 302, andCPU (controller) 101 that selects one of the sound signals output frommicrophones (sound collecting units) 302, based on the sound sourceposition information and the sound collecting unit placementinformation.

With this configuration, CPU 101 tends to be able to select appropriatemicrophone 302 that can collect the sound at the designated position.

Second Exemplary Embodiment

A second exemplary embodiment will be described with reference to FIGS.3 and 4.

FIG. 4 is an overhead view (a part of an entire seat layout)illustrating an example of a positional relationship between seats 401a, 401 b, and 401 c and microphones (sound collecting units) 302. Asound collecting system according to the second exemplary embodiment isdifferent from the sound collecting system according to the firstexemplary embodiment in a calculation method of sound source position P(step S101) and a calculation method of a direction to besound-collected (step S102), in the processes for selecting a microphonein the sound collecting device illustrated in FIG. 3. Otherconfigurations and operations are similar to those of the firstexemplary embodiment (see FIG. 1); therefore, the detailed descriptionthereof will not be given.

First, the calculation method of sound source position P (step S101) insound collecting device 100 according to the present exemplaryembodiment will be described. In the present exemplary embodiment, inputand output interface 206 of client 200 includes display 206 a and touchpanel 206 b (see FIG. 1). Memory 202 of client 200 stores data of thelayout of seats placed at predetermined positions in a space.

Display 206 a displays the layout. The user can designate an arbitraryseat, using the touch panel while viewing the layout displayed ondisplay 206 a. When the user designates the arbitrary seat, client 200sends a designated seat number (sound source position information) tosound collecting device 100 via network interface 203 in client 200.

Memory 102 (recording medium) in sound collecting device 100 stores alayout database associating positional coordinates of the seats withseat numbers, in the coordinate system that is arbitrarily defined inthe space where the sound collecting system is installed. In otherwords, the positions of the seats arranged in the predetermined spaceare included in specific position information indicating specificpositions, and the specific position information is stored in memory102.

Since a passenger sits on a seat, one of the positions of the seatsarranged in the predetermined space can be the sound source position.Therefore, when receiving the designation of the seat number, soundcollecting device 100 refers to the layout database of the seats storedin memory 102, and determines, as sound source position P, a positionalcoordinate of the seat associated with the designated seat number.

Next, the calculation method of the direction to be sound-collected(step S102) in the present exemplary embodiment will be described. Inthe present exemplary embodiment, seat arrangement direction Y of theseat associated with the designated seat number is determined as thedirection to be sound-collected. Seat arrangement direction Y refers toa direction to which a front surface of a backrest (a surface to bebrought into contact with the back of a sitting person) of thedesignated seat is directed. In other words, seat arrangement directionY refers to a direction to which the face of the passenger (person) isordinarily directed when the passenger sits on the seat.

When all the seats in the space are directed to the same seatarrangement direction, seat arrangement direction Y may be set as aprocessing parameter for CPU (controller) 101 in sound collecting device100. Further, when the seat arrangement direction in the space differsdepending on each seat, a plurality of seat arrangement directions Y maybe stored in the layout database of the seats, as information in whichseat arrangement directions Y are respectively associated with the seatnumbers. Further, CPU 101 may read seat arrangement direction Yassociated with the designated seat number from the layout database ofthe seats, and may set the direction as the direction to besound-collected. The subsequent processes are similar to those of thefirst exemplary embodiment; therefore, the detailed description thereofwill not be given.

To clarify a difference between the direction to be sound-collected inthe first exemplary embodiment and that in the second exemplaryembodiment, a description will be made with reference to FIG. 4. In FIG.4, seats 401 are illustrated by extracting seats 401 a, 401 b, and 401 cas a part of the seats arranged in the space. Of seats 401, seat 401 bis assumed to be designated as sound source position P.

Microphone 302 a is placed at the position in FIG. 4, which is spacedapart from sound source position P (the position where the passengersits) by distance Da, and its positional coordinate is expressed asmicrophone position Pa. In other words, microphone 302 a is located atplace Pa ahead of the sitting passenger, which is spaced apart from thepassenger by distance Da. Microphone 302 b is placed at the position inFIG. 4, which is spaced apart from sound source position P by distanceDb, and its positional coordinate is expressed as microphone positionPb. In other words, microphone 302 b is located at place Pb behind thesitting passenger, which is spaced apart from the passenger by distanceDb.

In those indications, face direction X in FIG. 2 is simply replaced withone of seat arrangement directions Y, and the processing method isunchanged. With this configuration, microphones 302 located within theangle range from −θ to +θ, that is, microphones 302 that is small inattenuation of a sound pressure level of a sound emitted at the seatposition and are located ahead in the seat arrangement direction tend tobe able to be selected.

For example, CPU (controller) 101 in sound collecting device 100 selectsa sound signal corresponding to a microphone (sound collecting unit) 302that has a minimum one of weighted distances (Dwa, Dwb) calculated basedon weighting factors (w1, w2) determined by a relative positionalrelationship between the sound source position information and the soundcollection unit placement information with one of seat arrangementdirections Y as a reference, and linear distances (Da, Db) between soundsource position P and respective microphones (sound collection units)302.

Further, sound source position P may be selected from one or more seatsarranged in a predetermined direction, and CPU 101 may select a soundcollecting unit that has a minimum one of linear distances betweenrespective microphones (sound collecting units) 302 and sound sourceposition P calculated based on the sound source position information andthe sound collecting unit placement information, of microphones (soundcollecting units) 302 present in the predetermined direction withrespect to sound source position P. Further, the predetermined directionmay be a frontward direction with respect to sound source position P.

Third Exemplary Embodiment

A third exemplary embodiment will be described with reference to FIGS. 5and 6. Configurations of a sound collecting system according to thethird exemplary embodiment are similar to those of the first exemplaryembodiment (see FIG. 1); therefore, the detailed description thereofwill not be given. For example, a configuration for designating soundsource position P is similar to that of the first exemplary embodiment.

FIG. 5 is an overhead view (a part of a layout) illustrating an exampleof a placement relationship among sound source position P, positions ofmicrophones (sound collecting units) 302, and an obstacle. In FIG. 5,the placed obstacle has the same height as a height of a space. In otherwords, the case described in FIG. 5 is a simple example that can behandled as a two-dimensional coordinate system in which heightinformation of sound source position P, position Pa of microphone 302 a,and position Pb of microphone 302 b can be ignored.

Origin O of a discrete coordinate system in the space, which isarbitrarily defined in the space, is assumed to be set at the positionin FIG. 5. Further, in the discrete coordinate system, dx is a minimumunit of distance defined in an x-direction (right direction in FIG. 5),and dy is a minimum unit of distance defined in a y-direction (downwarddirection in FIG. 5). Positions of a person and an object are expressedwith integral multiples of dx and dy. When sound source position P inFIG. 5 is designated as an arbitrary position in accordance with thecoordinate system, the coordinates of sound source position P are (3dx,4dy).

Microphone 302 a is placed at the position in FIG. 5, and positionalcoordinates Pa of microphone 302 a are (3dx, dy). Similarly, microphone302 b is placed at the position in FIG. 5, and positional coordinates Pbof microphone 302 b are (3dx, 6dy).

Further, an object having the same height as the height of the space isplaced as the obstacle at the position in FIG. 5. More specifically,coordinates (2dx, 2dy), (3dx, 2dy), (4dx, 2dy), (2dx, 3dy), (3dx, 3dy),and (4dx, 3dy) that correspond to a placement range of the object on thediscrete coordinates are assumed to be stored in memory (recordingmedium) 102 in sound collecting device 100 as a database (placementinformation of object).

Hereafter, an operation of sound collecting device 100 according to thepresent exemplary embodiment will be described, using the case with theabove placement relationship as an example.

FIG. 6 is a flowchart illustrating processes of sound collecting device100 according to the present exemplary embodiment. In FIG. 6, whenreceiving the designation of the sound source position from client 200,sound collecting device 100 calculates sound source position P (S301).Sound source position P is designated with a method similar to themethod described in the first exemplary embodiment. CPU (controller) 101calculates equations of line segments each connecting sound sourceposition P to position Pa of microphone 302 a and position Pb ofmicrophone 302 b, based on coordinates of sound source position P andthe coordinates of microphone 302 a and microphone 302 b (S302).

For example, when the coordinates of sound source position P are (Px1,Py1), and the coordinates of a position of one of microphones 302 are(Px2, Py2), an equation of a line segment connecting sound sourceposition P to the position of the one of microphones 302 can beexpressed as follows.

In Px1≠Px2,

Y=(Py2−Py1)/(Px2−Px1)×(X−Px1)+Py1,  (i)

-   -   where Px1<=X<=Px2 (assuming that Px1<Px2 is satisfied).

In Px1=Px2, and Py1≠Py2,

X=Px1,  (ii)

-   -   where Py1<=Y<=Py2 (assuming that Py1<Py2 is satisfied).

In the case of the example illustrated in FIG. 5, an equation of a linesegment connecting sound source position P to position Pa of microphone302 a can be expressed as follows.

X=3dx, where 1dy<=Y<=4dy.

Further, an equation of a line segment connecting sound source positionP to position Pb of microphone 302 b can be expressed as follows.

X=3dx, where 4dy<=Y<=6dy.

Next, CPU (controller) 101 selects a sound signal corresponding tomicrophone 302 that has a minimum one of linear distances between soundsource position P and the positions of respective microphones 302, ofmicrophones 302 in which the object is not present on the line segmentsconnecting sound source position P to the positions of respectivemicrophones 302, based on sound source position P, the position ofrespective microphones 302, and the placement information of the object.More specifically, CPU 101 first determines whether one or moremicrophones 302 in which the object is not present between sound sourceposition P and respective microphones 302 are present. Specifically, CPU101 determines whether each of the calculated equations of the linesegments passes through the placement range of the object. CPU 101determines microphone 302 corresponding to a line segment that does notpass through the placement range of the object (does not cross theobstacle) as microphone 302 in which the object is not present betweensound source position P and microphone 302 (S303). Memory (recordingmedium) 102 stores, as a database, digital values of all coordinatescorresponding to the placement range of the object, in the coordinatesystem arbitrarily defined in the space.

CPU 101 then determines whether the line segments pass through theplacement range of the object, by calculating digital values of allpossible coordinates taken by the equations of the line segmentscalculated in step S302, and comparing the calculated digital valueswith the coordinates at which the object is located, which are stored inthe database in memory 102.

In the example illustrated in FIG. 5, coordinate values (2dx, 2dy),(3dx, 2dy), (4dx, 2dy), (2dx, 3dy), (3dx, 3dy), and (4dx,3dy) correspondto the placement range of the object, and the equation of the linesegment connecting sound source position P to position Pa of microphone302 a can take coordinate values of (3dx, 2dy) and (3dx, 3dy).Accordingly, the line segment connecting sound source position P toposition Pa of microphone 302 a is determined to pass through theplacement range of the object. Whereas, the line segment connectingsound source position P to position Pb of microphone 302 b is determinednot to pass through the placement range of the object. With the aboveoperations, CPU 101 specifies microphones 302 in which the object is notpresent on the line segments connecting sound source position P to thepositions of respective microphones 302.

When determining that one or more microphones 302 corresponding to theline segments that do not pass through the placement range of the objectare present (Yes in S303), CPU 101 selects the sound signalcorresponding to microphone 302 that has the minimum one of the lineardistances from sound source position P to respective microphones 302, ofmicrophones 302 that are determined not to pass through the placementrange of the object (S304).

In other words, CPU (controller) 101 selects the sound signalcorresponding to microphone (sound collecting unit) 302 that has theminimum one of the linear distances between respective microphones(sound collecting units) 302 and sound source position P calculatedbased on the sound source position information and the sound collectingunit placement information, of microphones (sound collecting units) 302in which the object is not present on the line segments connecting soundsource position P to respective microphones (sound collecting units)302. Further, CPU 101 may select a sound signal corresponding tomicrophone 302 that has a minimum one of weighted distances calculatedbased on weighting factors that vary depending on whether the object ispresent on the line segments connecting sound source position P torespective microphones 302, and linear distances between sound sourceposition P and respective microphones 302.

When all microphones 302 are determined to pass through the placementrange of the object (No in S303), CPU 101 selects a sound signalcorresponding to microphone 302 that has a minimum one of the lineardistances from respective microphones 302 to sound source position P(S305).

In the case of the example illustrated in FIG. 5, only microphone 302 bis determined as microphone 302 corresponding to the line segment thatdoes not pass through the placement range of the object in step S303. Inother words, since microphone 302 b has the minimum one of the lineardistances between sound source position P and respective microphones 302of the microphones corresponding to the line segments that do not passthrough the placement range of the object, a sound signal correspondingto microphone 302 b is selected. With those operations, microphones 302in which the object is not present on the line segments connecting soundsource position P to the positions of microphones 302, that is,microphones 302 that are small in attenuation of sound pressure level,which is caused by the obstacle, tend to be able to be selected.

In the present exemplary embodiment, to simplify the description, thecase in which the coordinate system that is arbitrarily defined in thespace where the sound collecting system is installed can be handled as atwo-dimensional coordinate system ignoring the height information isdescribed, but a three-dimensional coordinate system considering theheight information may be used. In the case of the three-dimensionalcoordinate system, a height of the sound source position is calculatedbased on image data captured by two or more cameras 301 and thepositional coordinates of cameras 301 stored in memory 102.

Other Exemplary Embodiments

As described above, the first to third exemplary embodiments aredescribed as exemplifications of technique disclosed in the presentapplication. However, the technique in the present disclosure is notlimited thereto, and can be applied to exemplary embodiments subjectedto various modifications, substitutions, additions, and omissions.Further, new exemplary embodiments can be made by combining eachconstituent element described in the above first to third exemplaryembodiments. Hereinafter, other exemplary embodiments will be thenillustrated.

According to the first to third exemplary embodiments, in the soundcollecting system having the plurality of microphones (sound collectingunits) 302 placed in the space, sound collecting device 100appropriately selects one of microphones 302. However, a soundcollecting device that respectively replaces microphones 302 withmicrophone arrays configured with a plurality of microphone elements,and selects a sound signal obtained as a result of signal processing onsound signals from the microphone elements may be used.

According to the first to third exemplary embodiments, in the soundcollecting system having the plurality of microphones 302 placed in thespace, sound collecting device 100 selects one of microphones 302 thatis optimal for sound collection. However, a sound collecting device maybe configured to calculate weighted sum of the sound signals obtainedfrom the plurality of microphones 302, based on each certain condition,and to select the weighted sum of sound signals as the sound signal tobe sound-collected. More specifically, in FIGS. 2 and 4, the calculationof weighted sum may be performed by making weights for sound signalsobtained from microphones 302 located within the angle range from −θ to+θ relatively large, and making weights for sound signals obtained frommicrophones 302 located outside the angle range relatively small.Further, when the plurality of microphones 302 is present within theangle range from −θ to +θ, the weighting may be made larger as thedistance between sound source position P and the microphone positionbecomes smaller, and may be made smaller as the distance becomes larger.

The third exemplary embodiment concerns the sound collecting device forselecting the sound signal corresponding to microphone 302 that has theminimum one of the linear distances from sound source position P torespective microphones 302, of microphones 302 in which the object isnot present on the line segments connecting sound source position P tothe microphone positions. However, a sound collecting device may beconfigured to calculate weighting factors that vary depending on whetherthe object is present on the line segments connecting the sound sourceposition to the positions of respective microphones 302, based on theplacement information of the object, and to select a sound signalcorresponding to microphone 302 that has a minimum one of the weighteddistances calculated by multiplying the linear distances from the soundsource position to respective microphones 302 by the weighting factors.

Hereinbefore, the exemplary embodiments are described to exemplify thetechnology in the present disclosure, and therefore may be subjected tovarious modifications, substitutions, additions, and omissions withinthe scope of the claims or the scope equivalent thereto.

The present disclosure is applicable to a sound collecting device forsound collection at a designated position. More specifically, thepresent disclosure is applicable to, for example, a sound collectingdevice to be installed in a cabin of a mobile body such as an aircraft.

What is claimed is:
 1. A sound collecting device comprising: a soundsource position input interface that receives input of sound sourceposition information indicating a sound source position; an audiointerface that receives input of two or more sound signals collected bysound collecting units placed at predetermined positions in advance; arecording medium that stores sound collecting unit placement informationindicating placement information of the sound collecting units; and acontroller that selects one of the sound signals output from the soundcollecting units, based on the sound source position information and thesound collecting unit placement information.
 2. The sound collectingdevice according to claim 1, wherein the controller selects a soundsignal corresponding to a sound collecting unit that has a minimum oneof linear distances between the respective sound collecting units andthe sound source position calculated based on the sound source positioninformation and the sound collecting unit placement information, of thesound collecting units located within a predetermined angle rangecentering around a direction to be sound-collected with the sound sourceposition as a reference.
 3. The sound collecting device according toclaim 2, further comprising a video interface that receives input ofimages captured by one or more imaging units placed at predeterminedpositions in advance to capture images in a predetermined range, whereinthe recording medium further stores imaging unit placement informationindicating placement information of the imaging units, the controllerdetermines a face direction of a person appearing within a certaindistance range from the sound source position, and the controller setsthe face direction as the direction to be sound-collected.
 4. The soundcollecting device according to claim 2, wherein the recording mediumstores specific position information indicating one or more specificpositions in a predetermined space, and the sound source position isselected from the one or more specific positions.
 5. The soundcollecting device according to claim 4, wherein the specific positionsinclude a position of a seat arranged in the predetermined space.
 6. Thesound collecting device according to claim 5, wherein the direction tobe sound-collected is a direction in which the seat is arranged.
 7. Thesound collecting device according to claim 1, wherein the controllerselects a sound signal corresponding to a sound collecting unit that hasa minimum one of weighted distances calculated based on weightingfactors determined from a relative positional relationship between thesound source position information and the sound collection unitplacement information, and linear distances between the sound sourceposition and the respective sound collecting units.
 8. The soundcollecting device according to claim 7, further comprising a videointerface that receives input of images output from one or more imagingunits placed at predetermined positions in advance to capture images ina predetermined range, wherein the recording medium further storesimaging unit placement information indicating placement information ofthe imaging units, the controller determines a face direction of aperson appearing within a certain distance range from the sound sourceposition, and the controller selects a sound signal corresponding to asound collecting unit that has a minimum one of weighted distancescalculated based on weighting factors determined from a relativepositional relationship between the sound source position informationand the sound collection unit placement information with the facedirection as a reference, and linear distances between the sound sourceposition and the respective sound collecting units.
 9. The soundcollecting device according to claim 7, wherein the recording mediumstores specific position information indicating one or more specificpositions in a predetermined space, and the sound source position isselected from the one or more specific positions.
 10. The soundcollecting device according to claim 9, wherein the specific positionsinclude a position of a seat arranged in the predetermined space. 11.The sound collecting device according to claim 10, wherein thecontroller selects a sound signal corresponding to a sound collectingunit that has a minimum one of weighted distances calculated based onweighting factors determined from a relative positional relationshipbetween the sound source position information and the sound collectionunit placement information with a direction in which the seat isarranged, as a reference, and linear distances between the sound sourceposition and the respective sound collecting units.
 12. The soundcollecting device according to claim 1, wherein the controller selects asound signal corresponding to a sound collecting unit that has a minimumone of linear distances between the respective sound collecting unitsand the sound source position calculated based on the sound sourceposition information and the sound collecting unit placementinformation, of the sound collecting units present in a predetermineddirection with respect to the sound source position.
 13. The soundcollecting device according to claim 12, wherein the sound sourceposition is selected from one or more seats arranged in a predetermineddirection, and the controller selects a sound signal corresponding to asound collecting unit that has a minimum one of linear distances betweenthe respective sound collecting units and the sound source positioncalculated based on the sound source position information and the soundcollecting unit placement information, of the sound collecting unitspresent ahead of the sound source position.
 14. The sound collectingdevice according to claim 1, wherein the recording medium further storesplacement information of an object fixedly placed in a predeterminedspace, and the controller specifies sound collecting units in which theobject is not present on line segments connecting the sound sourceposition to the respective sound collecting units, based on theplacement information of the object, and selects a sound signalcorresponding to a sound collecting unit that has a minimum one oflinear distances between the respective sound collecting units and thesound source position calculated based on the sound source positioninformation and the sound collecting unit placement information, of thesound collecting units in which the object is not present on the linesegments.
 15. The sound collecting device according to claim 1, whereinthe recording medium further stores placement information of an objectfixedly placed in a predetermined space, and the controller selects asound signal corresponding to a sound collecting unit that has a minimumone of weighted distances calculated based on weighting factors thatvary depending on whether the object is present on line segmentsconnecting the sound source position to the respective sound collectingunits, and linear distances between the sound source position and therespective sound collecting units, based on the placement information ofthe object.
 16. A sound collecting method comprising: a first step ofreceiving input of sound source position information indicating a soundsource position; a second step of receiving input of two or more soundsignals collected by sound collecting units placed at predeterminedpositions in advance; and a third step of selecting one of the soundsignals output from the sound collecting units, based on the soundsource position information and sound collecting unit placementinformation indicating placement information of the sound collectingunits.
 17. The sound collecting method according to claim 16, whereinthe third step includes selecting a sound signal corresponding to asound collecting unit that has a minimum one of weighted distancescalculated based on weighting factors determined from a relativepositional relationship between a position indicated by the sound sourceposition information and positions indicated by the sound collectionunit placement information, and linear distances between the soundsource position and the respective sound collecting units.
 18. The soundcollecting method according to claim 16, wherein the third step includesselecting a sound signal corresponding to a sound collecting unit thathas a minimum one of linear distances between the respective soundcollecting units and the sound source position calculated based on thesound source position information and the sound collecting unitplacement information, of the sound collecting units present in apredetermined direction with respect to the sound source position. 19.The sound collecting method according to claim 16, wherein the thirdstep includes specifying sound collecting units in which an object isnot present on line segments connecting the sound source position to therespective sound collecting units, based on placement information of theobject fixedly placed in a predetermined space, and selecting a soundsignal corresponding to a sound collecting unit that has a minimum oneof linear distances between the respective sound collecting units andthe sound source position calculated based on the sound source positioninformation and the sound collecting unit placement information, of thesound collecting units in which the object is not present on the linesegments.
 20. The sound collecting method according to claim 16, whereinthe third step includes calculating weighting factors that varydepending on whether an object is present on line segments connectingthe sound source position to the respective sound collecting units,based on placement information of the object fixedly placed in apredetermined space, and selecting a sound signal corresponding to asound collecting unit that has a minimum one of weighted distancescalculated based on the weighting factors and linear distances betweenthe sound source position and the respective sound collecting units.